高层建筑模态抗震设计中的多模态静力推覆分析

将模态推覆分析方法与用自适应的加载方式相结合,提出了一种改进的多模态静力推覆分析方法.运用模态推覆分析将多自由度体系解耦成每阶模态对应的单自由度体系,对于每阶模态下的推覆分析,当结构进入塑性阶段后,采用自适应的加载方式,得到每阶模态下结构的反应.将结构推至每阶振型下的目标位移,采用SRSS组合的方式得到结构的响应.对应每阶振型下推覆分析的目标位移采用非弹性能力谱方法来计算.对不同高度的多高层钢框架-混凝土核心筒混合结构在8度罕遇地震下抗震性能进行了评估.结果显示,本文的静力推覆分析所得的结构响应同非线性动力时程分析所得的结果吻合较好.

Application of Performance-Based Seismic Design Method for the Seismic Evaluation of Hybrid Structures

An improved multi-mode pushover analysis,which combines the advantage of the modal pushover analysis(MPA) and the adaptive pushover analysis(APA),has been proposed.In the multi-mode pushover analysis procedure,the multiple degree-of-freedom(MDOF) system can approximately be decomposed into equivalent single degree-offreedom(ESDOF) system of multi-mode.The response of each modal pushover analysis can be attained by using adaptive load pattern when the structures enter into plasticity.The target displacement of each mode pushover analysis can be obtained by inelastic spectrum.Numerical examples of different tall hybrid structures are calculated to evaluate the accuracy by comparing the structural responses of the proposed analysis procedure with the results of the nonlinear history analysis(NHA).It shows that the structural responses of the proposed pushover analysis are generally similar to the results from the NHA,especially in the story drift.